a, b = map(int, input().split())
s = input()

ans = 'Yes'

length = len(s)

for x in range(length):
    if x == a and s[x] != '-':
        ans = 'No'
        break

    if ('0' > s[x] and s[x] > '9') or s[x] == '-':
        ans = 'No'
        break

print(ans)
