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: n=int(input())

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

Python: n=int(input())
ans_list=[]

for i in range(n):
	a=int(input())
	b=int(input())
	if max(a,b,a+b)>=10**80:
		ans_list.append("overflow")
	else:
		ans_list.append(a+b)

for i in ans_list:
	print(i)

Python: if __name__ == '__main__':
    N = int(input())
    for _ in range(N):
        a = input()
        b = input()
        c = str(int(a) + int(b))
        if len(a) > 80 or len(b) > 80 or len(c) > 80:
            print("overflow")
        else:
            print(c)

Python: import math

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

main()

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: import math

n = int(input())

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

Python: import math

N = int(input())
for i in range(N):
    a = int(input())
    b = int(input())
    if math.log10(a) > 79 or math.log10(b) > 79 or math.log10(a + b) > 79:
        print("overflow")
    else:
        print(a + b)

Python: '''
Created on Mar 21, 2013

@author: wukc
'''

from sys import stdin

n=int(stdin.readline())
for i in range(n):
    a,b=[stdin.readline().strip().lstrip("0") for k in range(2)]
    if len(a)>80 or len(b)>80:
        print("overflow")
        continue
    a,b=a.rjust(len(b),'0'),b.rjust(len(a),'0')
    ans=[]
    c=0
    for x,y in zip(a[::-1],b[::-1]):
        t=int(x)+int(y)+c
        c=t//10
        ans+=[t%10]
    ans+=[c]
    ans="".join(map(str,ans[::-1])).lstrip("0")
    if len(ans)>80:
        print("overflow")
        continue
    print(ans.rjust(1,'0'))

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(v)
            
    
if __name__ == '__main__':
    main()

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):
	print(sum(A[start:end]))
	start+=n
	end+=n

Python: '''
Created on Mar 21, 2013

@author: wukc
'''

from sys import stdin

n=int(stdin.readline())
for i in range(n):
    a,b=[stdin.readline().strip().lstrip("0") for k in range(2)]
    if len(a)>80 or len(b)>80:
        print("overflow")
        continue
    a,b=a.rjust(len(b),'0'),b.rjust(len(a),'0')
    ans=[]
    c=0
    for x,y in zip(a[::-1],b[::-1]):
        t=int(x)+int(y)+c
        c=t//10
        ans+=[t%10]
    ans+=[c]
    ans="".join(map(str,ans[::-1])).lstrip("0")
    if len(ans)>80:
        print("overflow")
        continue
    print(ans)

Python: for x in range(input()):
    x = input() + input()
    print("{:.80g}".format(x) if x < 1E79 else "overflow")

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

Python: import math

c  = raw_input();

for var in range(0, int(c)) :
	n1 = raw_input();
	n2 = raw_input();
	sum = int(n1) + int(n2);

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

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

Python: def main():
    n = int(input())
    answers = []
    for _ in range(n):
        a = input()
        b = input()
        la, lb = len(a), len(b)
        if la > 80 or lb > 80:
            answers.append("overflow")
            continue
        if la > lb:
            ll = la
            for _ in range(la-lb):
                b = "0" + b
        else:
            ll = lb
            for _ in range(lb-la):
                a = "0" + a
        ans = ""
        bl = 0
        for i in range(ll):
            tmp = int(a[ll-i-1]) + int(b[ll-i-1]) + bl
            if tmp >= 10:
                bl = 1
                tmp = tmp % 10
            else:
                bl = 0
            ans = str(tmp) + ans
        if bl == 1:
            ans = "1" + ans
        if len(ans) > 80:
            answers.append("overflow")
            continue
        answers.append(ans)
    print(*answers, sep="\n")

if __name__ == "__main__":
    main()