#include <stdio.h>

long long gcd (long long a, long long b) {
  if (b <= 0LL) {
    return a;
  }
  return gcd(b, a%b);
}

int main () {
  int n = 0;
  long long a[200000] = {};
  
  int res = 0;
  
  res = scanf("%d", &n);
  for (int i = 0; i < n; i++) {
    res = scanf("%lld", a+i);
  }
  
  if (gcd(a[0], a[1]) != 1LL || a[0]*a[1] == 0LL) {
    printf("0\n");
    printf("1 2\n");
    n--;
    while (n > 1) {
      printf("1 %d\n", n);
      n--;
    }
  } else if (n <= 2) {
    printf("%lld\n", (a[0]-1LL)*(a[1]-1LL));
    printf("1 2\n");
  } else if (n > 3) {
    printf("0\n");
    if (a[0]%2LL == 0LL && a[2]%2LL == 0LL) {
      printf("1 3\n");
      n--;
    } else if (a[0]%2LL == 0LL || (a[1]%2LL == 0LL && a[2]%2LL == 0LL)) {
      printf("2 3\n");
      n--;
    } else if (a[1]%2LL == 0LL) {
      printf("1 3\n");
      n--;
    } else if (a[2]%2LL == 0LL) {
      printf("1 2\n");
      n--;
    } else {
      printf("1 2\n");
      n--;
      printf("1 2\n");
      n--;
      printf("%d %d\n", n-1, n);
      n--;
    }
    while (n > 1) {
      printf("1 %d\n", n);
      n--;
    }
  } else if (gcd((a[0]-1LL)*(a[1]-1LL), a[2]) != 1LL) {
    printf("0\n");
    printf("1 2\n");
    printf("1 2\n");
  } else if (gcd(a[0], a[2]) != 1LL || a[2] == 0LL || gcd((a[0]-1LL)*(a[2]-1LL), a[1]) != 1LL) {
    printf("0\n");
    printf("1 3\n");
    printf("1 2\n");
  } else if (gcd((a[1]-1LL)*(a[2]-1LL), a[0]) != 1LL) {
    printf("0\n");
    printf("2 3\n");
    printf("1 2\n");
  } else {
    long long max = 0LL;
    int argmax = 0;
    for (int i = 0; i < n; i++) {
      if (max < a[i]) {
        max = a[i];
        argmax = i;
      }
    }
    printf("%lld\n",(a[0]-1LL)*(a[1]-1LL)*(a[2]-1LL)-max+1LL);
    printf("%d %d\n", (argmax+1)%3+1, (argmax+2)%3+1);
    printf("1 2\n");
  }
  
  return 0;
}