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#include <iostream>
#include <cstdio>
#include <string>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;
int main() {
    int n;
    scanf("%d", &n);
    int ones = 0;
    for (int i = 0; i < n; ++i) {
        int di;
        scanf("%d", &di);
        if (di == 1) {
            ++ones;
        }
    }
    int x;
    if (ones >= 2) {
        x = 0;
    } else if (ones == 1) {
        x = 1;
    } else {
        x = 2;
    }
    printf("%d\n", x);

    printf("2\n");
    printf("1 2\n");

    return 0;

}