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>
using namespace std;
int main(){
  int n,d[]={5,7,5,7,7},i,j,t,k;
  while(cin>>n,n){
    string s[41];
    for(i=0;i<n;i++)cin>>s[i];
    for(i=0,k=0;k!=5;i++)
      for(j=i,t=s[i].size(),k=0;k!=5;t+=s[++j].size())
	if(t==d[k])k++,t=0;
	else if(t>d[k])break;
    cout<<i<<endl;
  }
  return 0;
}

C++: #include <iostream>
#define FOR(i,k,n) for (int (i)=(k); (i)<(n); ++(i))
#define REP(i,n) FOR(i,0,n)
using namespace std;


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

int main(){
    int n;
    while(cin >> n && n != 0){
        int w[n],pos = 0;
        string str;
        REP(i,n){
            cin >> str;
            w[i] = str.length();
        }
        REP(i,n){
            int a,s;
            s = i;
            REP(j,5){
                a = 0;
                int l = w[s];
                while(l < gositigo[j]){
                    a++;
                    l += w[s + a];
                }
                if(l != gositigo[j]){goto NEXT;}
                s += a + 1;
            }
            pos = i+1;
            break;
            NEXT: continue;
        }
        cout << pos << endl;
    }
    return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
  int a[]={5,7,5,7,7},n,i,j,c,k;
  while(cin>>n,n){
    string s[n];
    for(i=0;i<n;i++)cin>>s[i];
    for(i=0;i<n;i++){
      c=k=0;
      for(j=i;j<n;j++){
        c+=s[j].size();
        if(c==a[k]){
          c=0;
          if(++k==5)goto L;
        }
      }
    }
    L:cout<<i+1<<endl;
  }
}

C++: #include<bits/stdc++.h>
using namespace std;
int n,l[45],L[45],a,d[5]={5,7,5,7,7};
string s;
 
int main(){
  while(1){
    cin>>n;
    if(!n)break;
    for(int i=1;i<=n;i++){
      cin>>s,l[i]=s.size();
      L[i]=L[i-1]+l[i];
    }
    a=0;
    for(int i=1;i<=n;i++){
      int x=0,s=i;
      for(int j=i;j<=n;j++){
    if(L[j]-L[s-1]==d[x])x++,s=j+1;
    if(!a&&x==5)a=i,cout<<a<<endl;
      }
    }
  }
  return 0;
}

C++: #include<bits/stdc++.h>
#define N 45
using namespace std;
int n,l[N],L[N],ans;
int d[5]={5,7,5,7,7};
string s;

int main(){
  while(1){
    cin>>n;
    if(!n)break;
    for(int i=1;i<=n;i++){
      cin>>s,l[i]=s.size();
      L[i]=L[i-1]+l[i];
    }
    ans=0;
    for(int i=1;i<=n;i++){
      int idx=0,s=i;
      for(int j=i;j<=n;j++){
	if(L[j]-L[s-1]==d[idx])idx++,s=j+1;
	if(!ans&&idx==5)ans=i;
      }
    }
    cout<<ans<<endl;
  }
  return 0;
}

C++: #include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<cstdio>
#include<sstream>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
using namespace std;
//kaewasuretyuui
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef pair<int,pii> pip;
typedef vector<pip>vip;
const double PI=acos(-1);
const double EPS=1e-8;
const int inf=1e8;
int main(){
	int n;
	while(cin>>n,n){
		vi in(n);
		rep(i,n){
			string s;
			cin>>s;
			in[i]=s.size();
		}
		int t[5]={5,7,5,7,7};
		rep(i,n){
			vi co(5);
			int now=i;
			int nowc=0;
			while(1){
				co[nowc]+=in[now];
				now++;
				if(co[nowc]==t[nowc])nowc++;
				else if(co[nowc]>t[nowc])break;
				if(nowc==5){
					cout<<i+1<<endl;
					goto end;
				}
			}
		}
		end:;
	}
}

C++: #include<iostream>

using namespace std;

signed main(){

   while(1){
      int n;
      cin>> n;
      if(!n) break;

      int w[n];
      for(int i=0; i<n; i++){
         string s;
         cin>> s;
         w[i]=s.size();
      }
      int b[]={5, 7, 5, 7, 7};
      for(int i=0; i<n; i++){
         int a=0, p=0;
         for(int j=i; j<n; j++){
            a+=w[j];
            if(a>b[p]){
               goto turai;
            }else if(a==b[p]){
               p++;
               if(p==4) break;
               a=0;
            }
         }
         cout<< i+1<< endl;
         return 0;
         turai:;
      }

   }

   return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
  int a[]={5,7,5,7,7},n,i,j,c,k;
  while(cin>>n,n){
    string s[n];
    for(i=0;i<n;i++)cin>>s[i];
    for(i=0;i<n;i++){
      c=k=0;
      for(j=i;j<n;j++){
        c+=s[j].size();
        if(c==a[k]){
          c=0;
          if(++k==5)cout<<i+1<<endl;
        }
      }
    }
  }
}

C++: #include <bits/stdc++.h>
#include <string>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define shosu(n) setprecision(n)
using namespace std;

int main() {
  int n;
  while (cin >> n, n) {
    int ans = 0, key = 0;
    string s[n];
    rep(i, n) cin >> s[i];
    for (int i = 0; i < n; i++) {
      ans = 0;
      key = 0;
      for (int j = i; j < n; j++) {
        ans += s[j].size();
        if (ans == 5 && key == 0) {
          key = 1;
          ans = 0;
        } else if (ans > 5 && key == 0 || ans > 7 && key == 1 ||
                   ans > 5 && key == 2 || ans > 7 && key == 3 ||
                   ans > 7 && key == 4) {
          ans = 0;
          key = 0;
          break;
        } else if (ans == 7 && key == 1) {
          key = 2;
          ans = 0;
        } else if (ans == 5 && key == 2) {
          ans = 0;
          key = 3;
        } else if (ans == 7 && key == 3) {
          ans = 0;
          key = 4;
        } else if (ans == 7 && key == 4) {
          cout << i + 1 << endl;
        }
      }
    }
  }
  return 0;
}