MOD = 1000000007

L = int(input())
answer = 1
for i in range(L):
	P, E = map(int, input().split())
	# mult = ((E+1) * P^0 + E * P^1 + (E-1) * P^2 + ... + 1 * P^E)
	#      = (P + P^2 + ... + P^(E+1) - (E+1)) / (P-1)
	#      = (P * (P^(E+1) - 1) / (P-1) - (E+1)) / (P-1)
	#      = (P * (P^(E+1) - 1) - (P-1) * (E+1)) / (P-1)^2
	mult = (P * pow(P, E + 1, MOD) - P - (P - 1) * (E + 1)) * pow(P - 1, MOD - 3, MOD)
	answer = answer * mult % MOD

print(answer)