Go: package main

import (
        "fmt"
        "bufio"
        "os"
)

func main() {
        var n int
        var a, b string
        sc := bufio.NewScanner(os.Stdin)
        fmt.Scanf("%d", &n)
        for i := 0; i < n; i++ {
                sc.Scan()
                a = sc.Text()
                sc.Scan()
                b = sc.Text()

                if len(a) > len(b) {
                        s := add(a, b)
                        if s[len(a)] > 0 {
                                if len(a) >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i <= len(a);i++ {
                                                fmt.Printf("%d", s[len(a)-i])
                                        }
                                }
                                fmt.Printf("\n")
                        } else {
                                if len(a)-1 >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i < len(a);i++ {
                                                fmt.Printf("%d", s[len(a)-i-1])
                                        }
                                }
                                fmt.Printf("\n")
                        }
                } else {
                        s := add(b, a)
                        if s[len(b)] > 0 {
                                if len(b) >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i <= len(b);i++ {
                                                fmt.Printf("%d", s[len(b)-i])
                                        }
                                }
                                fmt.Printf("\n")
                        } else {
                                if len(b)-1 >= 80 {
                                        fmt.Printf("overflow")
                                } else {
                                        for i := 0; i < len(b);i++ {
                                                fmt.Printf("%d", s[len(b)-i-1])
                                        }
                                }
                                fmt.Printf("\n")
                        }
                }
        }
}

// expects ln > lm
func add(n string, m string) (s [100]int) {
        ln := len(n)
        lm := len(m)
        var sum [100]int

        for i := 0; i < ln; i++ {
                var s, t int
                s = int(n[ln-1-i]) - int('0')

                if lm - 1 - i >= 0 {
                        t = int(m[lm-1-i]) - int('0')
                } else {
                        t = 0
                }

                sum[i+1] = (s + t + sum[i]) / 10
                sum[i] = (s + t + sum[i]) % 10
        }

        return sum
}

Python: t=int(input())
for num in range(t):
	a=int(input())
	b=int(input())
	if len(str(a))<=80 and len(str(b))<=80 and len(str(a+b))<=80:
		print(a+b)
	else:
		print("overflow")

Python: n = int(input())

for i in range(n):
    x = input()
    y = input()
    ans = int(x) + int(y)
    if len(x) > 80 or len(y) > 80 or len(str(ans)) > 80:
        print("overflow")
    else:
        print(ans)

Python: import math

n1 = input();
n2 = input();
sum = int(n1) + int(n2);

if int(math.log10(sum)) + 1 > 80 :
	print("overflow");
else :
	print(sum);

Python: # -*- coding: utf-8 -*-
N = int(input())

for _ in range(N):
    a = int(input())
    b = int(input())
    s = str(a + b)
    limit = '1' + '0'*79
    if len(s) <= limit:
        print(s)
    else:
        print('overflow')

Python: n = int(input())
for _ in range(n):
    a = input()
    if len(str(a)) > 80:
        print("overflow")
        continue
    b = input()
    if len(str(b)) > 80:
        print("overflow")
        continue
    c = int(a) + int(b)
    if len(str(c)) > 80:
        print("overflow")
    else:
        print(c)

Python: n = int(input())

for i in range(n):
    a = int(input())
    b = int(input())

    if (a + b) < (10 ** 80):
        print(a + b)
    else:
        print("overflow")

Python: # python template for atcoder1
import sys
sys.setrecursionlimit(10**9)
input = sys.stdin.readline

n = int(input())
ans = []
for _ in range(n):
    a = int(input())
    b = int(input())
    s = a+b
    if s > 10**80-1:
        ans.append("overflow")
    else:
        ans.append(str(s))
print("\n".join(ans))

Python: import math

n = int(input())
for i in range(n):
    for i in range(2):
        x = int(input())
        y = int(input())
        result = x * y
        print(result) if math.log10(result) + 1 < 10 ** 80 else print("overflow")

Python: # -*- coding:utf-8 -*-

def main():
    for i in range(int(input())):
        a=int(input())+int(input())
        if la>=10**80:
            print("overflow")
        print(a)
            
    
if __name__ == '__main__':
    main()

Python: n = int(input())
for _ in range(n):
    s = int(input()) + int(input())
    print('overflow' if len(str(s)) > 80 else s)

Python: import sys
import math as mas

n=int(input())
for t in range(n):
	i=int(t)
	a=int(input())
	b=int(input())
	a+=b
	if a<10**80:print(a)
	else:print("overflow")
	
#for i in sys.stdin:
#	a,b=map(int,i.split())
#	print(gcd(a,b),lcm(a,b))

Python: for i in range(int(input())):
    a = int(input()) + int(input())
    if a > 2147483647:
        print("overflow")
    else:
        print(a)

Python: a=int(input())
b=int(input())
c=a+b
c=str(c)
if len(c)>80:
	print("overflow")
else:
	print(c)

Python: n =int(input())
for i in range(n):
  a =int(input())
  b=int(input())

  if (a+b)<(10 **80):
    print(a+b)
  else:
    print("overflow")

Python: if __name__ == "__main__":
    nset = int(input())

    for i in range(0,nset):
        a = int(input())
        b = int(input())
        print(a+b)

Python: n = int(input())
for i in range(n):
    x = int(input())
    y = int(input())
    if len(str(x + y)) > 80:
        print("overflow")
    else:
        print(x + y)

Python: upper = 10**81
n = int(input())
for i in range(n):
    n1 = int(input())
    if n1 >= upper:
        print("overflow")
        continue
    n2 = int(input())
    if n2 >= upper:
        print("overflow")
        continue
    print( n1 + n2 if n1+n2 < upper else "overflow")

Python: #!/usr/bin/env python
#-*- coding:utf-8 -*-

import sys
import math

n = int(input())
anss = []

for _ in range(n):
    x = int(input())
    y = int(input())
    anss.append(x+y)

for data in anss:
    print(data)

Python: print("In preparation.")

Python: n = int(input())
for i in range(n):
    num1 = int(input())
    num2 = int(input())
    num3 = num1 + num2
    k = len(str(num3))
    if k > 80:
        print("overflow")
    else:
        print(num3)

Python: upper = 10**80
n = int(input())
for i in range(n):
    n1 = int(input())
    if n1 >= upper:
        print("overflow")
        continue
    n2 = int(input())
    if n2 >= upper:
        print("overflow")
        continue
    print( n1 + n2 if n1+n2 < upper else "overflow")

Python: #!/usr/bin/env python
#-*- coding:utf-8 -*-

import sys
import math

n = int(input())
anss = []

for _ in range(n):
    x = int(input())
    y = int(input())
    if int(math.log10(x)+1) > 80:
        print("overflow")
    elif int(math.log10(y)+1) > 80:
        print("overflow")
    elif int(math.log10(x+y)+1) > 80:
        print("overflow")
    else:
        anss.append(x+y)

for data in anss:
    print(data)

Python: n=int(input())
A=[]
while True:
	try:
		x=int(input())
		A.append(x)
	except EOFError:
		break
start=0
end=start+n
for i in range(len(A)//n):
	s=sum(A[start:end])
	if s/1e80>1:
		print("overflow")
	else:
		print(s)
	start+=n
	end+=n