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#include<cstdio>

int main() {
    int n,ai,ones; ones=0;
    scanf("%d",&n);
    for(int i=0; i<n; ++i) {
        scanf("%d",&ai);
        if(ai==1) ones++;
        if(ones >=2) break;
    }
    if(ones >=2) printf("%d\n",0);
    else
        if(ones == 1) printf("%d\n",1);
        else printf("%d\n",2);
    printf("%d\n",2);
    printf("%d %d\n",1,2);

return 0;
}