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

    result = a + b
    if len(str(result)) > 80:
        print('overflow')
    else:
        print(result)

Python: import sys

a = int(input())
b = int(input())
print(a + b)

Python: def main():
    n = int(input())

    for i in range(n):
        val1 = int(input())
        val2 = int(input())
        print(str(val1 + val2))

if __name__ == '__main__':
    main()

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

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

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

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

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

if __name__ == '__main__':
    main()

Python: 
if __name__ == '__main__':
    n = (int)(input())
    for _ in range(n):
        sNumber = (int)(input())
        tNumber = (int)(input())
        uNumber = sNumber+tNumber
        print("overflow" if uNumber >= 10**80 else uNumber)

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

Python: n=int(input())
for i in range(n):
    a=int(input())
    b=int(input())
    num=str(a+b)
    if len(num)>80:
        print("onerflow")
    else:
        print(num)

Python: from math import log10
n = int(input())
for i in range(n):
    a = int(input())
    b = int(input())
    c = a+b
    if (log10(c) > 80):
        print("overflow")
    else:
        print(c)

Python: ans = []
i = int(input())
for n in range(i):
    j = int(input())
    k = int(input())
    x = str(j + k)
    if len(x) >= 80:
        ans.append("overflow")
    else:
        ans.append(x)
for n in range(i):
    print(ans[n])

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

Python: import sys
import itertools

dataset_num = int(input())

class Overflow(Exception):
    pass

for _ in range(dataset_num):
    try:
        k1 = input()
        k2 = input()
        k1_val = [0] * 80
        k2_val = [0] * 80

        if len(k1) > 80 or len(k2) > 80:
            raise Overflow()
        
        for i, x in enumerate(reversed(k1)):
            k1_val[i] = int(x)

        for i, x in enumerate(reversed(k2)):
            k2_val[i] = int(x)
        
        res = [0] * 80
        for i in range(0, 80):
            res[i] += k1_val[i] + k2_val[i]
            if res[i] >= 10:
                res[i+1] += 1
                res[i] -= 10
        sumstr = "".join([str(x) for x in itertools.dropwhile(lambda x: x == 0, reversed(res))])
        if len(sumstr) > 80:
            raise Overflow()

        print(sumstr)
    except Overflow:
        print("overflow")

Python: N = 10 ** 80
for i in range(int(input())):
    n = int(input()) + int(input())
    print(n if n < N else 'overflow')

Python: n=int(input())
for _ in range(n):
    a=int(input())
    b=int(input())
    ab=a+b
    print(ab if ab<=10**80 else "overflow")

Python: for _ in range(int(input())):
    a=int(input())
    b=int(input())
    print([a+b,'overflow'][len(str(a+b))>80])

Python: if __name__ == '__main__':

	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: # ?????¶??????????±???????????????°??????
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(x + y)

if __name__ == '__main__':
    main()

Python: for _ in[0]*int(input()):
 s=int(input())+int(input())
 print([s,'overflow'][s>=10**80])

Python: p = int(input())
for j in range(p):
    a, b = int(input()), int(input())
    x = str(a+b)
    print("overflow" if len(x)>80 else a+b)