#include <bits/stdc++.h>
int main() {
  int a, b;
  scanf("%d %d", &a, &b);
  char num[255];
  scanf("%s", num);
  int counter = 0;
  for (int i = 0; num[i] != '\0'; i++) {
    if (num[a] != '-') {
      printf("No");
      return 0;
    }
    if (num[i] >= '0' && num[i] <= '9') {
      counter++;
    }
  }
  if (counter = a + b) {
    printf("Yes\n");
  } else {
    printf("No\n");
  }
  return 0;
}
