import java.io.*
import java.util.*
import kotlin.math.*

fun main() {
    
    solve()
    pw.flush()
    
}

fun solve() {
    
    val N = 3
    val a = nextIntarr(N).sorted()
    
    if( a[0] != a[1] && a[1] != a[2] ) pw.println(6-a.sum())
    else if( a[0] == a[1] && a[1] == a[2] ) pw.println(a[0])
    else if( a[0] == a[1] ) pw.println(a[2])
    else pw.println(a[0])
    
}

/* struct begin */

data class Point(val x: Int, val y: Int)
data class Edge(val from: Int, val to: Int, val w: Long)

class BinaryIndexedTree(n: Int) {
    
    val N = n
    var a = Array<Long>(N+1) {0L}
    
    fun sum(i: Int): Long {
        
        var idx = i+1
        var res = 0L
        while( idx > 0 ) {
            res += a[idx]
            idx -= idx and (-idx)
        }
        
        return res
        
    }
    
    fun add(i: Int, x: Long) {
        
        var idx = i+1
        while( idx <= N ) {
            a[idx] += x
            idx += idx and (-idx)
        }
        
    }
    
}

class UnionFind(N: Int) {
    
    var parent = Array<Int>(N) {it}
    var rank = Array<Int>(N) {1}
    var size = Array<Int>(N) {1}
    
    fun root(x: Int): Int {
        
        if( parent[x] == x ) {
            return x
        }else {
            parent[x] = root(parent[x])
            return parent[x]
        }
        
    }
    
    fun unite(x: Int, y: Int) {
        
        val rx = root(x)
        val ry = root(y)
        if( rx == ry ) return
        
        if( rank[rx] > rank[ry] ) {
            parent[ry] = rx
            size[rx] += size[ry]
        }else {
            parent[rx] = ry
            size[ry] += size[rx]
            if( rank[rx] == rank[ry] ) rank[ry]++
        }
        
    }
    
    fun same(x: Int, y: Int): Boolean = (root(x) == root(y))
    fun getSize(x: Int): Int = size[root(x)]
    
}

/* struct end */

/* math begin */

fun intceil(x: Double) = ceil(x).toInt()
fun intfloor(x: Double) = floor(x).toInt()
fun gcd(x: Int, y: Int): Int {
    
    var a = max(x, y)
    var b = min(x, y)
    var r: Int
    
    do {
        r = a%b
        a = b
        b = r
    }while( r > 0 )
    
    return a
    
}

/* math end */

/* I/O begin */

var st = StringTokenizer("")
val br = System.`in`.bufferedReader()
val pw = PrintWriter(System.out, false)

fun nextInt() = next().toInt()
fun nextLong() = next().toLong()
fun nextLine() = br.readLine()!!
fun nextDouble() = next().toDouble()
fun nextIntarr(n: Int) = Array<Int>(n) {nextInt()}
fun nextStrarr(n: Int) = Array<String>(n) {next()}
fun nextLongarr(n: Int) = Array<Long>(n) {nextLong()}

fun next(): String {
    
    while( !st.hasMoreTokens() ) st = StringTokenizer(br.readLine()!!)
    return st.nextToken()
    
}

/* I/O end */