Go: package main

import (
	"bufio"
	"fmt"
	"math/big"
	"os"
	"strconv"
)

var sc = bufio.NewScanner(os.Stdin)

func main() {
	sc.Scan()
	dataset, _ := strconv.Atoi(sc.Text())
	var firstdata *big.Int

	for i := 0; i < dataset*2; i++ {
		n := new(big.Int)
		sc.Scan()
		data, _ := n.SetString(sc.Text(), 10)

		if i%2 == 0 {
			firstdata = data
			continue
		}

		result := new(big.Int)
		if result := result.Add(data, firstdata); len(result.String()) > 80 {
			fmt.Println("overflow")
			continue
		} else {
			fmt.Println(result)
		}
	}
}

Python: m = 100000000000000000000000000000000000000000000000000000000000000000000000000000000
n = int(input())
for i in range(n):
    a = int(input())
    b = int(input())
    sum = a + b
    if sum > m or sum == m:
        print("overflow")
    else:
        print(sum)

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

Python: def f(): return int(raw_input())
n = f()
for _ in [0]*n:
  a = f()
  b = f()
  c = a+b
  print [c, "overflow"][len(str(c))>80]

Python: import math

n = int(input())

for i in range(0, n):
    a = int(input())
    b = int(input())
    if int(math.log10(a + b)) + 1 > 80:
        print("overflow")
    else :
        print(a + b)

Python: n = input()
for _ in [0]*n:
  a = input()
  b = input()
  c = a+b
  print [c,"overflow"][len(str(c))>80]

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

import math

BIG_NUM = 100000000000000000000000000000000000000000000000000000000000000000000000000000000


def main():
    n = int(input())
    for _ in range(n):
        a = int(input())
        b = int(input())
        if a >= BIG_NUM  or b >= BIG_NUM or a + b >= BIG_NUM:
            print("overflow")
        else:
            print(a+b)

if __name__ == "__main__":
    main()

Python: import sys
N=int(input())
N=int(N/2)
for i in range(N):
    a=input()
    b=input()
    len_a=len(a)
    len_b=len(b)
    c=[]
    kuriage=0
    if(len_a>=len_b):
        for i in range(len_b):
            c.append((kuriage+int(a[len_a-1-i])+int(b[len_b-1-i]))%10)
            kuriage=(kuriage+int(a[len_a-1-i])+int(b[len_b-1-i]))//10
        for i in range(len_b,len_a):
            c.append((kuriage+int(a[len_a-1-i]))%10)
            kuriage=(kuriage+int(a[len_a-1-i]))//10



    else :
        for i in range(len_a):
            c.append((kuriage+int(a[len_a-1-i])+int(b[len_b-1-i]))%10)
            kuriage=(kuriage+int(a[len_a-1-i])+int(b[len_b-1-i]))//10
        for i in range(len_a,len_b):
            c.append((kuriage+int(b[len_b-1-i]))%10)
            kuriage=(kuriage+int(b[len_b-1-i]))//10

    if(kuriage==1):
        c.append(1)

    if(len(c)>=80):
        print('overflow')

    else:
        for i in c[::-1]:
            print(i,end='')
        print('')

Python: num_datasets = int(input())

for i in range(num_datasets):
    n = input().strip()
    m = input().strip()
    first_num_str = ""
    second_num_str = ""
    if len(n) > len(m):
        first_num_str = n
        second_num_str = m
    else:
        first_num_str = m
        second_num_str = n
    total = ""
    carry = 0
    first_int = 0
    second_int = 0
    first_last_index = len(first_num_str)-1
    second_last_index = len(second_num_str)-1
    for i in range(len(first_num_str)):
        first_int = int(first_num_str[first_last_index-i])
        if i < len(second_num_str):
            second_int = int(second_num_str[second_last_index-i])
        else:
            second_int = 0
        added = (first_int + second_int + carry) % 10
        carry = (first_int + second_int + carry) // 10
        total = str(added) + total
    if carry > 0:
        total = str(carry) + total
    if len(total) > 80:
        print("overflow")
    else:
        print(total)

Python: import math
count=int(input())
for i in range(count):
    x=int(input())
    y=int(input())
    ans=x+y
    if int(math.log10(ans)>=80):
        print("overflow")
    else:
        print(ans)

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

Python: N = int(input())
for i in range(N):
    a = int(input())
    b = int(input())
    ans = a + b
    if len(str(ans)) > 80:
        print("overflow")
    else:
        print(ans)

Python: N = int(input())

list = []
for n in range(0, N):
    tmp = []
    for _ in range(0, 2):
        tmp.append(int(input()))
    list.append(tmp)

for a, b in list:
    c = a + b
    if c >= 10 ** 80:
        print('overflow')
    else:
        print(str(c))

Python: while True:
    n = int(input())
    for _ in range(n):
        a, b = int(input()), int(input())
        x = str(a+b)
        print('overflow' if len(x) > 80 else x)

Python: n = int(input())

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

Python: n=int(input())
for i in range(n):
	a=int(input())
	b=int(input())
	c=a+b
	if a>=int(1e80) or b>=int(1e80) or c>=int(1e80):
		print("overflow")
	else:
		print(c)

Python: N=int(input())
a=[None]*N
b=[None]*N
for i in range(0,N):
  a[i]=int(input())
  b[i]=int(input())
for i in range(0,N):
  if len(str(a[i]))>80:
    print("overflow")
  elif len(str(b[i]))>80:
    print("overflow")
  elif len(str(a[i]+b[i]))>80:
    print("overflow")
  else:
    print(a[i]+b[i])

Python: n=int(input())
for n in range(n):
	a=int(input())
	b=int(input())
	c=a+b
	if c>=int(1e79):
		print("overflow")
	else:
		print(c)

Python: while(True):
    try:
        n = input()
        for i in range(n):
            a = input()
            b = input()
            c = str(a + b)
            if(len(c) >= 80):
                print("overflow")
            else:
                print(c)
    except Exception:
        break

Python: for i in range(int(input())):
  ans = int(input()) + int(input())
  print(ans if len(str(ans)) <= 80 else "overflow")

Python: n = int(input())

for i in range(0, n):
    a = int(input())
    b = int(input())
    if len(str(a + b)) > 80:
        print("overflow")
    elif len(str(a)) > 80:
        print("overflow")
    elif len(str(b)) > 80:
        print("overflow")
    else :
        print(a + b)

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

for _ in range(N):
    a = int(input())
    b = int(input())
    s = str(a + b)
    if len(s) <= 80:
        print(s)
    else:
        print('overflow')

Python: # ?????¶??????????±???????????????°??????
import sys

def main():
    n = int(sys.stdin.readline().strip())

    for _ in range(n):
        x = sys.stdin.readline().strip()
        y = sys.stdin.readline().strip()

        if len(x) > 80 or len(y) > 80:
            print('overflow')
        else:
            ans = int(x) + int(y)
            if len(str(ans)) > 80:
                print('overflow')
            else:
                print(ans)

if __name__ == '__main__':
    main()

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

import sys
import math

def digit(x):
    d = 0
    while x >= 1:
        x /= 10
        d += 1

    return d

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

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

for data in anss:
    print(data)

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

def main():
    LIST=[]
    for i in range(int(input())):
        a=int(input())
        b=int(input())
        LIST.append(a+b)

        if len(LIST)>80:
            print("overflow")
            break

    for v in LIST:
        print(str(v))
            
    
if __name__ == '__main__':
    main()