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| #include <cstdio>
const int maxn = 1e5 + 5;
const int mo = 1e9 + 7;
using namespace std;
int ind[maxn], n, c, ans;
int pow(int x, int t){
int res = 1; x %= mo;
while (t > 0){
if (t & 1) res = 1ll * res * x % mo;
x = 1ll * x * x % mo;
t >>= 1;
}
return res;
}
int main(){
scanf("%d", &n);
for (int u, v, i = 1; i < n; i++){
scanf("%d%d", &u, &v);
ind[u]++, ind[v]++;
}
for (int i = 1; i <= n; i++)
if (ind[i] > 1) ++c;
int P = pow(2, c);
for (int i = 1; i <= n; i++)
if (ind[i] == 1) ans = (ans + 2ll * P % mo) % mo;
else ans = (ans + P) % mo;
printf("%d\n", ans);
return 0;
}
|