N=int(input())
X=[list(map(int,input().split())) for i in range(N)]
mod=10**9+7
ANS=1
for i in range(N):
  ANS=ANS*-((-pow(X[i][0],X[i][1]+2,mod)+X[i][1]*(X[i][0]-1)+2*X[i][0]-1)%mod*pow(X[i][0]-1,(mod-2)*2,mod)%mod)%mod
print(ANS)