#include <bits/stdc++.h>
using namespace std;
const int mod = 1000000007;
char s[105];
int main() {
  int n, nr = 0;
  gets(s);
  n = strlen(s);
  int x = 0;
  for (int i = 0; i < n; i++) x = (x * 2 + s[i] - '0') % mod;
  for (int i = 1; i < n; i++) x = (x * 2) % mod;
  printf("%d\n", x);
  return 0;
}
