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

C++: #include<iostream>
#include<string>
using namespace std;
int n,w[1000];
string str,kari;
int main(){

  cin >> n;
  while( n != 0){
    fill_n(w,1000,0);
    w[0] = 1;

    for(int i = 0;i < n;i++){
      cin >> kari;
      if(i != 0) w[str.size()] = i+1;
      str += kari;
    }
    
    for(int i = 0;i <= str.size()-31;i++){
      if(w[i]!=0&&w[i+5]!=0&&w[i+12]!=0&&w[i+17]!=0&&w[i+24]!=0){
	if(i+31 == str.size() || w[i+31] != 0){
	  cout << w[i] << endl;
	  break;
	}
      }
    }
    cin >> n;
  }

  return (0);
}

C++: #include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> VI;
typedef vector<VI> VVI;
const double PI = 3.14159265358979323846;
const double EPS = 1e-12;
const int INF = numeric_limits<int>::max() / 2;
const int NEG_INF = numeric_limits<int>::min() / 2;
const int MOD=1e9+7;

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

  int n;
  while(true){
      cin>>n;
      if(n==0) break;
      std::vector<string> v(n);
      for(int i=0;i<n;i++){
          cin>>v[i];
      }
      int tanku[5]={5,7,5,7,7};
      for(int i=0;i<n-1;i++){
          int cnt=0,idx=0;
          for(int j=0;i+j<n;j++){
              cnt+=v[i+j].length();
              //cout<<cnt<<" "<<idx<<endl;
              if(cnt<tanku[idx]) continue;
              else if(cnt==tanku[idx]){
                  idx++;
                  cnt=0;
              }
              else{
                  break;
              }
          }
          if(idx==5){
              cout<<i+1<<endl;
              break;
          }
      }
  }
  return 0;
}

C++: #include <stdio.h>
#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
int make(int k,int p);

vector<string> a(40);

int main() {
  int n;
  scanf ("%d",&n);
  while(n){

    for(int t=0;t<n;t++){
      //scanf ("%s",a[t]);
      cin >> a[t];
    }
    for(int t=n;t<40;t++){
      //scanf ("%s",a[t]);
      a[t]="";
    }
    int end=0;
    int k=0;
    for(k=0;k<n;k++){
      int q=k;
      if(make(q,5)>=1){
        q=1+make(q,5);
        if(make(q,7)>=1){
          q=1+make(q,7);
          if(make(q,5)>=1){
            q=1+make(q,5);
            if(make(q,7)>=1){
              q=1+make(q,7);
              if(make(q,7)>=1){
                q=1+make(q,7);
                end=1;
              }
            }
          }
        }
      }
      if(end==1) break;
    }
    printf("%d\n",k+1);
    scanf ("%d",&n);
  }
}


int make(int k,int p){
  int l=0;
  int r=0;
  l=a[k].size();
  if(l==p){
    return k;
  }
  else{
    if(l<p){
      r=make(k+1,p-l);
      return r;
    }
    else{
      return -1;
    }
  }
}