#include <bits/stdc++.h>
int main() {
  int A, B, i, j, k, n;
  char addr[10];
  char c;
  int boo = 1;
  int endflag = 0;
  scanf("%d", &A);
  scanf("%d", &B);
  scanf("%s", &addr);
  for (i = 0; i < A; i++) {
    if (addr[i] == '\0') {
      endflag = 1;
      boo = -1;
      break;
    }
    if (!(addr[i] >= '0' && addr[i] <= '9')) {
      endflag = 1;
      boo = -1;
      break;
    }
  }
  if (endflag != 1) {
    if (addr[A] != '-') {
      endflag = 1;
      boo = -1;
    }
  }
  for (i = A + 1; i < B; i++) {
    if (endflag == 1) break;
    if (addr[i] == '\0') {
      endflag = 1;
      boo = -1;
      break;
    }
    if (!(addr[i] >= '0' && addr[i] <= '9')) {
      endflag = 1;
      boo = -1;
      break;
    }
  }
  if (boo == 1)
    printf("Yes\n");
  else
    printf("No\n");
  return 0;
}
