#include <stdio.h>

int main(){
	int a,b;
	scanf("%d %d",&a,&b);
	char num[255];
	scanf("%s",num);
	int counter;
	
	for(int i=0;num!=EOF;i++){
		if(num[a]!='-'){
			printf("No");
			return 0;
		}
		if(num[i]>=48&&num[i]<=57){
			counter++;
		}
	}
	if(counter=a+b){
		printf("Yes");
	}
	else{
		printf("No");
	}
	return 0;
}