import math
def py():
    print("Yes")
def pn():
    print("No")
def iin():
    x = int(input())
    return x

neko = 0
nya = 0
nuko = 0

a,b = map(int,input().split())
s = input()
for x in range(len(s)):
    if s[x] == '-':
        break
if (a == x)and(b == len(s)-1-x):
    py()
else:
    pn()