# -*- coding: utf-8 -*-
num = list(map(int, input().split()))
string = input()
length = num[0] + num[1] + 1
flag = False
for i in range(num[0]):
    if string[i].isdigit():
        flag = True
    else :
        flag = False
        break

if string[num[0]] == '-':
    for i in range(num[0] + 1, length):
        if string[i].isdigit():
            flag = True
        else:
            flag = False
            break
else:
    flag = False

if flag == True:
    print("Yes")
else:
    print("No")
