line=input().split(' ')
s=input()
a=int(line[0])
b=int(line[1])
c=['0','1','2','3','4','5','6','7','8','9']
m=0
for n in range(a+1+b):
  if n==a:
    if s[n]!='-':
      print('No')
      break
  elif s[n] in c:
    m+=1

if m==a+b:
  print('Yes')
else:
  print('No')