#include using namespace std; //#define int long long #define rep(i,n) for(int (i)=0;(i)<(int)(n);(i)++) #define rept(i,n) for(int (i)=0;(i)<=(int)(n);(i)++) #define reps(i,s,n) for(int (i)=(s);(i)<(int)(n);(i)++) #define repst(i,s,n) for(int (i)=(s);(i)<=(int)(n);(i)++) #define repr(i,n) for(int (i)=(n);(i)>=0;(i)--) #define each(itr,v) for(auto (itr):(v)) #define all(c) (c).begin(),(c).end() #define pb push_back #define mp(x,y) make_pair((x),(y)) #define fi first #define se second #define chmin(x,y) x=min(x,y) #define chmax(x,y) x=max(x,y) #define ln '\n' #define dbg(x) cout<<#x" = "<<(x)< vi; typedef vector vl; typedef vector > mat; typedef pair pii; typedef pair pll; const int inf = (int)1e9; const ll linf = (ll)1e18; const int mod = (int)(1e9+7); const int dx[] = {0, 1, 0, -1}; const int dy[] = {1, 0, -1, 0}; const int ddx[] = {0, 1, 1, 1, 0, -1, -1, -1}; const int ddy[] = {1, 1, 0, -1, -1, -1, 0, 1}; const double eps = 1e-10; struct oreno_initializer { oreno_initializer() { cin.tie(0); ios::sync_with_stdio(0); } } oreno_initializer; // ━━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥… // .。.:( ^ω^)・゚+.。.:( ^ω^)・゚+.。.:( ^ω^)・゚+.。.:( ^ω^)・゚+.。.:( ^ω^)・゚+ // ・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・‥…━━━☆・ int n, a[100000], x; signed main() { cin >> n; x = n; rep(i,n) cin >> a[i]; repr(i,n-1) if (a[i]==x) x--; cout << x << ln; }