# B
a, b = map(int, input().split())
s = input()
n = len(s)
nums = list(range(10))
point = 0
flag = 'Yes'

while (0<=point<=n-1):
    if point == a:
        if s[point] != '-':
            flag = 'No'
    else:
        if int(s[point]) not in nums:
            flag = 'No'
    point += 1
print(flag)