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#include <stdio.h>
#include <stdlib.h>

#define MAXN 102400

int main() {
  int v[MAXN];
  int n, i, t1;
  scanf("%d", &n);
  t1 = 0;
  for (i=0;i<n && t1<2;i++) {
    int x;
    scanf("%d", &x);
    if (x==1)
      t1++;
  }
  printf("%d\n2\n1 2\n", 2-t1);
  return 0;
}