Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	io := NewIo()
	defer io.Flush()
	for {
		n := io.NextInt()
		if n == 0 {
			break
		}
		s := make([]string, n)
		for i := 0; i < n; i++ {
			s[i] = io.NextLine()
		}
		w := [5]int{5, 7, 5, 7, 7}
		ans := 0
	OUTER:
		for i := 0; i < n; i++ {
			cnt, wc := 0, 0
			for j := i; j < n; j++ {
				wc += len(s[j])
				if wc == w[cnt] {
					cnt++
					wc = 0
					if cnt == 5 {
						ans = i + 1
						break OUTER
					}
				} else if wc > w[cnt] {
					break
				}
			}
		}
		io.Println(ans)
	}
}

// I/O template
type Io struct {
	reader    *bufio.Reader
	writer    *bufio.Writer
	tokens    []string
	nextToken int
}

func NewIo() *Io {
	return &Io{
		reader: bufio.NewReader(os.Stdin),
		writer: bufio.NewWriter(os.Stdout),
	}
}

func (io *Io) Flush() {
	err := io.writer.Flush()
	if err != nil {
		panic(err)
	}
}

func (io *Io) NextLine() string {
	var buff []byte
	for {
		line, isPrefix, err := io.reader.ReadLine()
		if err != nil {
			panic(err)
		}
		buff = append(buff, line...)
		if !isPrefix {
			break
		}
	}
	return string(buff)
}

func (io *Io) Next() string {
	for io.nextToken >= len(io.tokens) {
		line := io.NextLine()
		io.tokens = strings.Fields(line)
		io.nextToken = 0
	}
	s := io.tokens[io.nextToken]
	io.nextToken++
	return s
}

func (io *Io) NextInt() int {
	i, err := strconv.Atoi(io.Next())
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) NextFloat() float64 {
	i, err := strconv.ParseFloat(io.Next(), 64)
	if err != nil {
		panic(err)
	}
	return i
}

func (io *Io) Println(a ...interface{}) {
	fmt.Fprintln(io.writer, a...)
}

func (io *Io) Printf(format string, a ...interface{}) {
	fmt.Fprintf(io.writer, format, a...)
}

func (io *Io) PrintIntSlice(a []int) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func (io *Io) PrintStringSlice(a []string) {
	b := make([]interface{}, 0, len(a))
	for _, x := range a {
		b = append(b, x)
	}
	io.Println(b...)
}

func Log(name string, value interface{}) {
	fmt.Fprintf(os.Stderr, "%s=%+v\n", name, value)
}

func ExampleIo() {
	io := NewIo()
	defer io.Flush()
	a := make([]int, 0, 3)
	a[0], a[1], a[2] = io.NextInt(), io.NextInt(), io.NextInt()
	io.Println(a)
	io.PrintIntSlice(a)
	Log("io", a)
}

C++: #include<iostream>
#include<cstring>
using namespace std;

int num[6]={5,7,5,7,7};
int n;
int t[55];

bool check(int a,int s=0,int i=0){
	if(s>num[i])return false;
	if(s==num[i])i++,s=0;
	if(i==5)return true;
	if(a>=n)return false;
	return check(a+1,s+t[a],i);
}

int main(){
	int i,j,k;
	int a,b,c;
	char ca[15];
	while(cin>>n){
		if(!n)break;
		for(i=0;i<n;i++){
			cin>>ca;
			t[i]=strlen(ca);
		}
		for(i=0;i<n;i++){
			if(check(i)){
				cout<<i+1<<endl;
				break;
			}
		}
	}
}

C++: #include<iostream>
#include<algorithm>
#include<vector>
#include<string>
using namespace std;

int main() {
	int n;
	cin >> n;

	while (n)
	{
		vector<string> w;
		for (int i = 0;i < n;++i) {
			string tmp;
			cin >> tmp;
			w.push_back(tmp);
		}

		int flag = 0;
		int len = 0;
		int output = 100000000;
		for (int i = 0;i < n;++i) {
			flag = 0;
			len = 0;
			for (int j = i; j< n;++j) {
				len += w[j].size();
				if (flag == 0 || flag == 2) {
					if (len == 5) {
						len = 0;
						flag++;
					}
					else if (len > 5) {
						break;
					}
				}
				else {
					if (len == 7) {
						len = 0;
						flag++;
					}
					else if (len > 7) {
						break;
					}
				}
			}

			if (flag >= 5) {
				output = i + 1;
				break;
			}
		}

		cout << output << endl;
	}


}

C++: #include<iostream>
#include<vector>
#include<string>
#include<cstdlib>
#include<sstream>
#include<queue>
#include<deque>
#include<cmath>
#include<algorithm>
#include<stack>
#include<map>
#include<set>
#include<iomanip>
#define INF 2147483647
#define lli long long int
#define MOD 1000000007
#define pb push_back

using namespace std;
typedef vector<int> vi;
typedef vector< vector<int> > vvi;
typedef pair<int,int> pii;
typedef vector<pair<int,int>> vpii;
int main() {
	while(1){
		int n; cin >> n;
		if (n == 0) break;
		
		vector<string> str(n);
		for(int i = 0; i < n; i++) {
			cin >> str[i];	
		}

		int ans = 0;
		for(int i = 0; i < n; i++) {
			ans = i;	
			vector<int> check = {5,7,5,7,7};
			int idx = 0;
			for (int j = i; j < n; j++) {
					if (check[idx] > 0){
						check[idx] -= str[j].size();
					}else if(check[idx] <= 0){
						idx++;
						check[idx] -= str[j].size();
					}
					
			}
			int sum = 0;
			for (int k = 0; k < 5; k++){
				sum += check[k];
			}
			if (sum == 0){
				break;
			}

		}
		cout << ans + 1 << endl;
	}

	return 0;
}

C++: #include<bits/stdc++.h>
int i,j,d[50],p,n,q,a[5]={5,7,5,7,7};
char s[15];
main(){
	for(n=1;n;){
		scanf("%d",&n);
		for(i=0;i<n;i++){
			scanf("%s",s);
			d[i]=strlen(s);
		}
		for(i=0;n;i++){
			p=i;
			for(j=0;j<5;j++){
				q=a[j];
				while(q>0){
					q-=d[p];p++;
				}
				if(q<0)break;
			}
			if(j>4){
				printf("%d\n",i+1);
				break;
			}
		}
	}
}

C++: #include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "iomanip"

using namespace std;

const long long int MOD = 1000000007;

long long int N, M, K, H, W, L, R;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> N;
	while (N) {
		vector<int>num(N);
		vector<int>sum(N);
		for (int i = 0; i < N; i++) {
			string s;
			cin >> s;
			num[i] = s.size();
		}
		for (int i = 0; i < N; i++) {
			M = 0;
			K = 0;
			for (int j = i; j < N; j++) {
				M += num[j];
				if (M == 5 || M == 12 || M == 17 || M == 24 || M == 31) {
					K++;
				}
			}
			if (K == 5) {
				cout << i + 1 << endl;
				break;
			}
		}
		cin >> N;
	}

	return 0;
}

C++: #define _USE_MATH_DEFINES
#define INF 0x3f3f3f3f

#include <iostream>
#include <cstdio>
#include <sstream>
#include <cmath>
#include <cstdlib>
#include <algorithm>
#include <queue>
#include <stack>
#include <limits>
#include <map>
#include <string>
#include <cstring>
#include <set>
#include <deque>
#include <bitset>
#include <list>
#include <cctype>
#include <utility>
  
using namespace std;
  
typedef long long ll;
typedef pair <int,int> P;
typedef pair <int,P> PP;
  
static const double EPS = 1e-8;
  
int tx[] = {0,1,0,-1};
int ty[] = {-1,0,1,0};

int main(){
  int num_word;
  while(~scanf("%d",&num_word)) {
    if (num_word == 0) break;
    
    vector<string> words;
    for (int word_i = 0; word_i < num_word; word_i++) {
      string word;
      cin >> word;
      words.push_back(word);
    }
    int res = 0;
    for (int start = 0; start < num_word; start++) {
      bool has_end[50];
      memset(has_end, 0, sizeof(has_end));
      int pos = 0;
      for (int word_i = start; word_i < num_word; word_i++) {
	pos += words[word_i].size();
	has_end[pos] = true;
      }

      if (has_end[5] && has_end[5 + 7] && has_end[5 + 7 + 5]
	  && has_end[5 + 7 + 5 + 7] && has_end[5 + 7 + 5 + 7 + 7]) {
	res = start + 1;
	break;
      }
    }
    printf("%d\n",res);
  }
}