1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | #include <cstdio>
int main() {
int N;
scanf("%d", &N);
int leafs = 0;
int degree;
while (N--)
{
scanf("%d", °ree);
if (degree == 1)
++leafs;
if (leafs == 2)
break;
}
printf("%d\n2\n1 2\n", 2 - leafs);
return 0;
}
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