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 <string>
#include <cstdio>
using namespace std;

int main(){
  int n,a,b,c,d,e,j;
  string w[40];
  while(true){
    cin >> n;
    if(n == 0) break;

    for(int i = 0; i < n; i++){
      cin >> w[i];
    }
    //cout << "n="<<n << endl;
    for(int i = 0; i < n - 4; i++){
      //start w[i] 5 7 5 7 7
      //cout << i << "=i" <<endl;
      a = 5;
      b = 7;
      c = 5;
      d = 7;
      e = 7;

      int j=i;
      bool flag = true;
      while(flag ){//5

        if(a - w[j].size() == 0){j++; break;}
        else if(j >= n){flag = false;}
        else if(a - w[j].size() > 0){a-=w[j].size(); j++;}
        else {flag = false;}
      }
      //cout << j << endl;
      while(flag){//7

        if(b - w[j].size() == 0){j++; break;}
        else if(j >= n ){flag = false;}
        else if(b - w[j].size() > 0){b-=w[j].size(); j++;}
        else {flag = false;}
      }
      //cout << j << endl;
      while(flag){//5

        if(c - w[j].size() == 0){j++; break;}
        else if(j >= n){flag = false;}
        else if(c - w[j].size() > 0){c-=w[j].size(); j++;}
        else {flag = false;}
      }
      //cout << j << endl;
      while(flag){//7

        if(d - w[j].size() == 0){j++; break;}
        else if(j >= n){flag = false;}
        else if(d - w[j].size() > 0){d-=w[j].size(); j++;}
        else {flag = false;}

      }
      //cout <<  j << endl;
      while(flag){//7

        if(e - w[j].size() == 0){  j++; break;}
        else if(j >= n){flag = false;}
        else if(e - w[j].size() > 0){  e -= w[j].size(); j++;}
        else {flag = false;}
      }
      if(flag){
        cout << i+1 << endl;
        break;
      }
    }
  }

  return 0;

}

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

int s[]={5,7,5,7,7};

int main(){
    int n;
    while(cin>>n&&n!=0){
        vector<int> w(n);
        string tmp;
        for(int i=0;i<n;i++){
            cin >> tmp;
            w[i] = tmp.size();
        }
        for(int i=0;i<n;i++){
            int x=0;
            int y=0;
            for(int j=i;j<n;j++){
                x += w[j];
                if(x==s[y]){
                    if(y==4){
                        cout << i+1 << endl;
                        goto lll;
                    }
                    x = 0;
                    y++;
                }else if(x>s[y]){
                    break;
                }
            }
        }
        lll:;
    }
    return 0;
}

C++: #include "bits/stdc++.h"
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define rep(i,n) for(ll i=0;i<(ll)(n);i++)
#define all(a)  (a).begin(),(a).end()
#define pb push_back
#define INF (1e9+1)
//#define INF (1LL<<59)

int main(){
	int n;
	while(cin>>n&&n){
		vector<int> v(n);
		rep(i,n){
			string s;
			cin>>s;
			v[i] = s.size();
		}
		
		rep(i,n){
			int now;
			int pos = i;
			
			int p[]={5,7,5,7,7};
			rep(j,5){
				now=0;
				while(now<p[j]){
					now+=v[pos++];
					if(now==p[j])break;
					if(now>p[j])goto next;
				}
			}
			cout<<i+1<<endl;
			break;
next:;
		}
	}
}

C++: #include<bits/stdc++.h>
using namespace std;

int main(){
  int step,flag=0,n,l,x;
  while(1){
    cin >> n;
    if(n==0){break;}
    string w[n];
    for(int i=0;i<n;i++){
      cin >> w[i];
    }
    for(int i=0;i<n;i++){
      l=0;
      step=1;
      flag=0;
      x=i;
      while(1){
        if(flag==1){break;}
        l+=w[x].length();
        switch(step){
          case 1:
          if(l>5){flag=1;}
          else if(l==5){step++;}
          break;
          case 2:
          if(l>12){flag=1;}
          else if(l==12){step++;}
          break;
          case 3:
          if(l>17){flag=1;}
          else if(l==17){step++;}
          break;
          case 4:
          if(l>24){flag=1;}
          else if(l==24){step++;}
          break;
          case 5:
          if(l>31){flag=1;}
          else if(l==31){flag=2;}
          break;
        }
        if(flag==2){break;}
        x++;
      }
      if(flag==2){x=i+1;break;}
    }
    if(flag==2){cout << x << endl;}
  }
  return 0;
}