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mod=1000000007
n=input()
n=int(n)
ans=0
h=[0 for i in range(1005)]
a=[[0 for i in range(1005)]for i in range(1005)]
for i in range(1,n+1):
    for j in range(1,i+1):
        if i==1 and j==1:
            a[i][j]=1
        else:
            a[i][j]=(j*a[i-1][j-1]+j*a[i-1][j])%mod
        if i==n:
            ans=(ans+a[i][j])%mod
print(ans)
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX