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#include <cstdio>
using namespace std;

int read() { int n; scanf("%d", &n); return n; }

int main() {
    int n = read();
    int r = 2;
    for (int i=0; i<n && r>0; ++i) if (read() == 1) --r;
    printf("%d\n2\n1 2\n", r);
}