#include <bits/stdc++.h>

 using namespace std;
 char str[1<<4];
 int main(){
 	int A , B;
   scanf("%d%d",&A,&B);
   scanf("%s",str+1);
   if(strlen(str+1) != A+B + 1){
    printf("No");
     return 0;
   }
   for(int i = 1 ; i <= A+B+1; ++i){
   		if(i <= A and (str[i] > '9' or str[i] < '0') ){
         	printf("No");
          return 0;
        }else if(i == A+1 and str[i] ! '-'){
        	printf("No");
          return 0;
        }else if(i > A+1 and (str[i] > '9' or str[i] < '0')){
        	printf("No");
          	return 0;
        }
   }
   printf("Yes");
 }
   