#include<bits/stdc++.h>

using namespace std;

int main () {
    int n; scanf("%d", &n);

    int dx[] = {0, 1, 2, 2, 1, -1, -2, -2, -1};
    int dy[] = {0, 2, 1, -1, -2, -2, -1, 1, 2};

    int burx[] = {0, 1, 2, 2, 5};
    int bury[] = {0, 3, 3, 5, 4};

    int cav[] = {4, 3}, c = 0;

    for(int k = 1; k <= n; k++){
        int mov;
        scanf("%d", &mov);
        c++;
        cav[0] += dx[mov];
        cav[1] += dy[mov];
        for(int i = 1; i <=4; i++){
            if(cav[0] == burx[i] && cav[1] == bury[i]){
                printf("%d", c);
                return 0;
            }
        }
    }
    printf("%d", c);
}