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#include <stdio.h>

using namespace std;

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

    long long vertex;
    long long totalOnes = 0;
    while (n--){
        scanf("%lld", &vertex);
        if (vertex == 1){
            totalOnes += 1;
        }


    }

    long long x;
    if (totalOnes>=2){
        x = 0;
    } else {
        if (totalOnes==1) {
            x = 1;
        } else {
            x = 2;
        }
    }
    printf("%lld\n", x);

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

    return 0;
}