#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     int a[100005];     cin >> n;     int fa = 1;     for (int i = 1; i <= n; i++) {       cin >> a[i];       if (a[i] != i) {         fa = 0;       }     }     if (fa == 1) {       cout <<  0 ;     } else {       int ji = n - 1;       while (a[ji] < a[ji + 1]) {         ji--;       }       cout << ji;     }   }   