#include <bits/stdc++.h>
int main() {
  int A, B;
  scanf("%d %d", &A, &B);
  char c[A + B + 2];
  scanf("%s", c);
  for (int i = 0; i < A + B + 1; i++) {
    if (i != A && (0 > c[i] - '0' || c[i] - '0' > 9)) {
      printf("No\n");
    } else if (c[i] != '-') {
      printf("No\n");
    }
  }
  printf("Yes");
}
