# [rustfmt :: skip ] pub struct Writer < W : Write > {writer : BufWriter < W > , }
# [rustfmt :: skip ] impl < W : Write > Writer < W > {pub fn new (write : W ) -> Self {Self {writer : BufWriter :: new (write ) , } } pub fn ln < S : Display > (& mut self , s : S ) {writeln ! (self . writer , "{}" , s ) . expect ("Failed to write." ) } pub fn out < S : Display > (& mut self , s : S ) {write ! (self . writer , "{}" , s ) . expect ("Failed to write." ) } pub fn join < S : Display > (& mut self , v : & [S ] , separator : & str ) {v . iter () . fold ("" , | sep , arg | {write ! (self . writer , "{}{}" , sep , arg ) . expect ("Failed to write." ) ; separator } ) ; writeln ! (self . writer ) . expect ("Failed to write." ) ; } pub fn bits (& mut self , i : i64 , len : usize ) {(0 .. len ) . for_each (| b | write ! (self . writer , "{}" , i >> b & 1 ) . expect ("Failed to write." ) ) ; writeln ! (self . writer ) . expect ("Failed to write." ) } pub fn flush (& mut self ) {let _ = self . writer . flush () ; } }
# [rustfmt :: skip ] pub struct Reader < F > {init : F , buf : VecDeque < String > , }
# [rustfmt :: skip ] mod reader_impl {use super :: {BufRead , Reader , VecDeque , FromStr as FS } ; impl < R : BufRead , F : FnMut () -> R > Iterator for Reader < F > {type Item = String ; fn next (& mut self ) -> Option < String > {if self . buf . is_empty () {let mut reader = (self . init ) () ; let mut l = String :: new () ; reader . read_line (& mut l ) . unwrap () ; self . buf . append (& mut l . split_whitespace () . map (ToString :: to_string ) . collect () ) ; } self . buf . pop_front () } } impl < R : BufRead , F : FnMut () -> R > Reader < F > {pub fn new (init : F ) -> Self {let buf = VecDeque :: new () ; Reader {init , buf } } pub fn v < T : FS > (& mut self ) -> T {let s = self . next () . expect ("Insufficient input." ) ; s . parse () . ok () . expect ("Failed to parse." ) } pub fn v2 < T1 : FS , T2 : FS > (& mut self ) -> (T1 , T2 ) {(self . v () , self . v () ) } pub fn v3 < T1 : FS , T2 : FS , T3 : FS > (& mut self ) -> (T1 , T2 , T3 ) {(self . v () , self . v () , self . v () ) } pub fn v4 < T1 : FS , T2 : FS , T3 : FS , T4 : FS > (& mut self ) -> (T1 , T2 , T3 , T4 ) {(self . v () , self . v () , self . v () , self . v () ) } pub fn v5 < T1 : FS , T2 : FS , T3 : FS , T4 : FS , T5 : FS > (& mut self ) -> (T1 , T2 , T3 , T4 , T5 ) {(self . v () , self . v () , self . v () , self . v () , self . v () ) } pub fn vec < T : FS > (& mut self , length : usize ) -> Vec < T > {(0 .. length ) . map (| _ | self . v () ) . collect () } pub fn vec2 < T1 : FS , T2 : FS > (& mut self , length : usize ) -> Vec < (T1 , T2 ) > {(0 .. length ) . map (| _ | self . v2 () ) . collect () } pub fn vec3 < T1 : FS , T2 : FS , T3 : FS > (& mut self , length : usize ) -> Vec < (T1 , T2 , T3 ) > {(0 .. length ) . map (| _ | self . v3 () ) . collect () } pub fn vec4 < T1 : FS , T2 : FS , T3 : FS , T4 : FS > (& mut self , length : usize ) -> Vec < (T1 , T2 , T3 , T4 ) > {(0 .. length ) . map (| _ | self . v4 () ) . collect () } pub fn chars (& mut self ) -> Vec < char > {self . v :: < String > () . chars () . collect () } fn split (& mut self , zero : u8 ) -> Vec < usize > {self . v :: < String > () . chars () . map (| c | (c as u8 - zero ) as usize ) . collect () } pub fn digits (& mut self ) -> Vec < usize > {self . split (b'0' ) } pub fn lowercase (& mut self ) -> Vec < usize > {self . split (b'a' ) } pub fn uppercase (& mut self ) -> Vec < usize > {self . split (b'A' ) } pub fn char_map (& mut self , h : usize ) -> Vec < Vec < char > > {(0 .. h ) . map (| _ | self . chars () ) . collect () } pub fn bool_map (& mut self , h : usize , ng : char ) -> Vec < Vec < bool > > {self . char_map (h ) . iter () . map (| v | v . iter () . map (| & c | c != ng ) . collect () ) . collect () } pub fn matrix < T : FS > (& mut self , h : usize , w : usize ) -> Vec < Vec < T > > {(0 .. h ) . map (| _ | self . vec (w ) ) . collect () } } }
# [rustfmt :: skip ] pub trait ToLR < T > {fn to_lr (& self ) -> (T , T ) ; }
# [rustfmt :: skip ] impl < R : RangeBounds < T > , T : Copy + BoundedAbove + BoundedBelow + One + Add < Output = T > > ToLR < T > for R {fn to_lr (& self ) -> (T , T ) {use Bound :: {Excluded , Included , Unbounded } ; let l = match self . start_bound () {Unbounded => T :: min_value () , Included (& s ) => s , Excluded (& s ) => s + T :: one () , } ; let r = match self . end_bound () {Unbounded => T :: max_value () , Included (& e ) => e + T :: one () , Excluded (& e ) => e , } ; (l , r ) } }
# [rustfmt :: skip ] pub use std :: {cmp :: {max , min , Ordering , Reverse } , collections :: {hash_map :: RandomState , BTreeMap , BTreeSet , BinaryHeap , HashMap , HashSet , VecDeque , } , convert :: Infallible , convert :: {TryFrom , TryInto } , fmt :: {Debug , Display , Formatter } , hash :: Hash , io :: {stdin , stdout , BufRead , BufWriter , Read , Write } , iter :: {repeat , Product , Sum } , marker :: PhantomData , mem :: swap , ops :: {Add , AddAssign , BitAnd , BitAndAssign , BitOr , BitOrAssign , BitXor , BitXorAssign , Bound , Deref , DerefMut , Div , DivAssign , Index , IndexMut , Mul , MulAssign , Neg , Not , Range , RangeBounds , Rem , RemAssign , Shl , ShlAssign , Shr , ShrAssign , Sub , SubAssign , } , str :: {from_utf8 , FromStr } , } ;
#[allow(unused_macros)]
macro_rules ! chmax {($ base : expr , $ ($ cmps : expr ) ,+ $ (, ) * ) => {{let cmp_max = max ! ($ ($ cmps ) ,+ ) ; if $ base < cmp_max {$ base = cmp_max ; true } else {false } } } ; }
#[allow(unused_macros)]
macro_rules ! max {($ a : expr $ (, ) * ) => {{$ a } } ; ($ a : expr , $ b : expr $ (, ) * ) => {{if $ a > $ b {$ a } else {$ b } } } ; ($ a : expr , $ ($ rest : expr ) ,+ $ (, ) * ) => {{let b = max ! ($ ($ rest ) ,+ ) ; if $ a > b {$ a } else {b } } } ; }
#[allow(unused_macros)]
macro_rules ! chmin {($ base : expr , $ ($ cmps : expr ) ,+ $ (, ) * ) => {{let cmp_min = min ! ($ ($ cmps ) ,+ ) ; if $ base > cmp_min {$ base = cmp_min ; true } else {false } } } ; }
#[allow(unused_macros)]
macro_rules ! min {($ a : expr $ (, ) * ) => {{$ a } } ; ($ a : expr , $ b : expr $ (, ) * ) => {{if $ a > $ b {$ b } else {$ a } } } ; ($ a : expr , $ ($ rest : expr ) ,+ $ (, ) * ) => {{let b = min ! ($ ($ rest ) ,+ ) ; if $ a > b {b } else {$ a } } } ; }
#[allow(unused_macros)]
macro_rules ! chmax {($ base : expr , $ ($ cmps : expr ) ,+ $ (, ) * ) => {{let cmp_max = max ! ($ ($ cmps ) ,+ ) ; if $ base < cmp_max {$ base = cmp_max ; true } else {false } } } ; }
#[allow(unused_macros)]
macro_rules ! max {($ a : expr $ (, ) * ) => {{$ a } } ; ($ a : expr , $ b : expr $ (, ) * ) => {{if $ a > $ b {$ a } else {$ b } } } ; ($ a : expr , $ ($ rest : expr ) ,+ $ (, ) * ) => {{let b = max ! ($ ($ rest ) ,+ ) ; if $ a > b {$ a } else {b } } } ; }
#[allow(unused_macros)]
macro_rules ! dbg {($ ($ x : tt ) * ) => {{# [cfg (debug_assertions ) ] {std :: dbg ! ($ ($ x ) * ) } # [cfg (not (debug_assertions ) ) ] {($ ($ x ) * ) } } } }
# [rustfmt :: skip ] pub use algebra_traits :: {AbelianGroup , Associative , Band , BoundedAbove , BoundedBelow , Commutative , CommutativeMonoid , Group , Idempotent , Invertible , Magma , MapMonoid , Monoid , One , Pow , PrimitiveRoot , SemiGroup , Unital , Zero , } ;
# [rustfmt :: skip ] mod algebra_traits {use super :: Debug ; pub trait Magma {type M : Clone + PartialEq + Debug ; fn op (x : & Self :: M , y : & Self :: M ) -> Self :: M ; } pub trait Associative {} pub trait Unital : Magma {fn unit () -> Self :: M ; } pub trait Commutative : Magma {} pub trait Invertible : Magma {fn inv (x : & Self :: M ) -> Self :: M ; } pub trait Idempotent : Magma {} pub trait SemiGroup : Magma + Associative {} pub trait Monoid : Magma + Associative + Unital {fn pow (& self , x : Self :: M , mut n : usize ) -> Self :: M {let mut res = Self :: unit () ; let mut base = x ; while n > 0 {if n & 1 == 1 {res = Self :: op (& res , & base ) ; } base = Self :: op (& base , & base ) ; n >>= 1 ; } res } } pub trait CommutativeMonoid : Magma + Associative + Unital + Commutative {} pub trait Group : Magma + Associative + Unital + Invertible {} pub trait AbelianGroup : Magma + Associative + Unital + Commutative + Invertible {} pub trait Band : Magma + Associative + Idempotent {} impl < M : Magma + Associative > SemiGroup for M {} impl < M : Magma + Associative + Unital > Monoid for M {} impl < M : Magma + Associative + Unital + Commutative > CommutativeMonoid for M {} impl < M : Magma + Associative + Unital + Invertible > Group for M {} impl < M : Magma + Associative + Unital + Commutative + Invertible > AbelianGroup for M {} impl < M : Magma + Associative + Idempotent > Band for M {} pub trait MapMonoid {type Mono : Monoid ; type Func : Monoid ; fn op (& self , x : & < Self :: Mono as Magma > :: M , y : & < Self :: Mono as Magma > :: M , ) -> < Self :: Mono as Magma > :: M {Self :: Mono :: op (x , y ) } fn unit () -> < Self :: Mono as Magma > :: M {Self :: Mono :: unit () } fn apply (& self , f : & < Self :: Func as Magma > :: M , value : & < Self :: Mono as Magma > :: M , ) -> < Self :: Mono as Magma > :: M ; fn identity_map () -> < Self :: Func as Magma > :: M {Self :: Func :: unit () } fn compose (& self , f : & < Self :: Func as Magma > :: M , g : & < Self :: Func as Magma > :: M , ) -> < Self :: Func as Magma > :: M {Self :: Func :: op (f , g ) } } pub trait Zero {fn zero () -> Self ; } pub trait One {fn one () -> Self ; } pub trait BoundedBelow {fn min_value () -> Self ; } pub trait BoundedAbove {fn max_value () -> Self ; } pub trait Pow {fn pow (self , exp : i64 ) -> Self ; } pub trait PrimitiveRoot {fn primitive_root () -> Self ; } }
# [rustfmt :: skip ] pub trait Integral : 'static + Send + Sync + Copy + Ord + Display + Debug + Add < Output = Self > + Sub < Output = Self > + Mul < Output = Self > + Div < Output = Self > + Rem < Output = Self > + AddAssign + SubAssign + MulAssign + DivAssign + RemAssign + Sum + Product + BitOr < Output = Self > + BitAnd < Output = Self > + BitXor < Output = Self > + Not < Output = Self > + Shl < Output = Self > + Shr < Output = Self > + BitOrAssign + BitAndAssign + BitXorAssign + ShlAssign + ShrAssign + Zero + One + BoundedBelow + BoundedAbove {}
macro_rules ! impl_integral {($ ($ ty : ty ) ,* ) => {$ (impl Zero for $ ty {fn zero () -> Self {0 } } impl One for $ ty {fn one () -> Self {1 } } impl BoundedBelow for $ ty {fn min_value () -> Self {Self :: min_value () } } impl BoundedAbove for $ ty {fn max_value () -> Self {Self :: max_value () } } impl Integral for $ ty {} ) * } ; }
impl_integral!(i8, i16, i32, i64, i128, isize, u8, u16, u32, u64, u128, usize);
pub fn main() {
    let stdin = stdin();
    let stdout = stdout();
    solve(Reader::new(|| stdin.lock()), Writer::new(stdout.lock()));
}
pub trait MillerRabin {
    fn is_prime(&self) -> bool;
}
impl MillerRabin for u64 {
    fn is_prime(&self) -> bool {
        if *self < 2 || *self & 1 == 0 {
            return *self == 2;
        }
        let mont = MontgomeryU64::new(*self);
        let is_composite = |mut checker: u64| -> bool {
            if checker >= *self {
                checker %= self;
            }
            if checker == 0 {
                return false;
            }
            let mut tr = mont.pow(checker, mont.d);
            if tr == mont.r || tr == mont.r_neg {
                return false;
            }
            (1..mont.k).all(|_| {
                tr = mont.mul(tr, tr);
                tr != mont.r_neg
            })
        };
        const MILLER_RABIN_BASES_32: [u64; 3] = [2, 7, 61];
        const MILLER_RABIN_BASES_64: [u64; 7] = [2, 325, 9375, 28178, 450775, 9780504, 1795265022];
        if *self < 1 << 32 {
            MILLER_RABIN_BASES_32.iter()
        } else {
            MILLER_RABIN_BASES_64.iter()
        }
        .all(|&checker| !is_composite(checker))
    }
}

#[derive(Clone, Debug)]
pub struct MontgomeryU64 {
    pub n: u64,
    pub n_inv: u64,
    pub nh: u64,
    pub r: u64,
    pub r_neg: u64,
    pub r_pow2: u64,
    pub d: u64,
    pub k: u32,
}
impl MontgomeryU64 {
    #[inline]
    pub fn new(n: u64) -> Self {
        debug_assert_eq!(n & 1, 1);
        let n_inv = (0..5).fold(n, |x, _a| {
            x.wrapping_mul(2u64.wrapping_sub(n.wrapping_mul(x)))
        });
        debug_assert_eq!(n.wrapping_mul(n_inv), 1);
        let nh = (n >> 1) + 1;
        let r = n.wrapping_neg() % n;
        let r_neg = n - r;
        let r_pow2 = ((n as u128).wrapping_neg() % (n as u128)) as u64;
        let k = (n - 1).trailing_zeros();
        let d = (n - 1) >> k;
        Self {
            n,
            n_inv,
            nh,
            r,
            r_neg,
            r_pow2,
            d,
            k,
        }
    }
    #[inline]
    pub fn add(&self, a: u64, b: u64) -> u64 {
        debug_assert!(a < self.n);
        debug_assert!(b < self.n);
        let (t, fa) = a.overflowing_add(b);
        let (u, fs) = t.overflowing_sub(self.n);
        if fa || !fs {
            u
        } else {
            t
        }
    }
    #[inline]
    pub fn sub(&self, a: u64, b: u64) -> u64 {
        debug_assert!(a < self.n);
        debug_assert!(b < self.n);
        let (t, f) = a.overflowing_sub(b);
        if f {
            t.wrapping_add(self.n)
        } else {
            t
        }
    }
    #[inline]
    pub fn ar(&self, a: u64) -> u64 {
        debug_assert!(a < self.n);
        self.mul(a, self.r_pow2)
    }
    #[inline]
    pub fn mul(&self, ar: u64, br: u64) -> u64 {
        debug_assert!(ar < self.n);
        debug_assert!(br < self.n);
        let t: u128 = (ar as u128) * (br as u128);
        let (t, f) = ((t >> 64) as u64).overflowing_sub(
            ((((t as u64).wrapping_mul(self.n_inv) as u128) * self.n as u128) >> 64) as u64,
        );
        if f {
            t.wrapping_add(self.n)
        } else {
            t
        }
    }
    #[inline]
    pub fn pow(&self, a: u64, mut b: u64) -> u64 {
        debug_assert!(a < self.n);
        let mut ar = self.ar(a);
        let mut t = if b & 1 == 0 { self.r } else { ar };
        b >>= 1;
        while b != 0 {
            ar = self.mul(ar, ar);
            if b & 1 != 0 {
                t = self.mul(t, ar);
            }
            b >>= 1;
        }
        t
    }
}

pub fn solve<R: BufRead, W: Write, F: FnMut() -> R>(mut reader: Reader<F>, mut writer: Writer<W>) {
    let n: usize = reader.v();
    let mut a = reader.vec::<u64>(n);
    let a_set = a.iter().cloned().collect::<HashSet<_>>();
    a.sort();
    let mut cur = Vec::new();
    let mut ans = -1;
    let mut l = 1;
    for i in 2..=5000000 {
        if i.is_prime() {
            let mut k = i;
            let mut ng = false;
            let mut b = Vec::new();
            while k > 0 {
                if !a_set.contains(&(k % 10)) {
                    ng = true;
                    break;
                }
                b.push(k % 10);
                k /= 10;
            }
            if !ng {
                cur.append(&mut b);
                cur.sort();
                cur.dedup();
            } else {
                if cur == a {
                    chmax!(ans, (i - 1 - l) as i64);
                }
                cur = Vec::new();
                l = i + 1;
            }
        }
    }
    if cur == a {
        chmax!(ans, (5000000 - l) as i64);
    }
    writer.ln(ans);
}