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>
using namespace std;
int main() {
	int n;
	const int sp[] = { 5,7,5,7,7 };
	while (cin >> n, n){
		int a[41];
		for (int i = 0; i < n; i++) {
			string s; cin >> s;
			a[i] = s.size();
		}
		for (int i = 0; i < n; i++) {
			int cnt = 0, k = 0;
			for (int j = 0;; j++) {
				cnt += a[i + j];
				if (cnt == sp[k]) {
					k++;
					if (k == 5) {
						cout << i + 1 << endl;
						goto end;
					}
					cnt = 0;
				}
				else if (cnt > sp[k])break;
			}
		}
	end:;
	}
}

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

int main(){
  cin.tie(0);
ios::sync_with_stdio(false);
  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 <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <bitset>
#include <cmath>
#include <string>
#define FI first
#define SE second
#define PF push_front
#define PB push_back
#define POF pop_front
#define POB pop_back
#define MA make_pair
#define ll long long
#define VE vector<int>
#define VP vector<pair<int,int> >
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ROF(i,a,b) for(int i=b-1;i>=a;i--)
#define YES(i) cout<<(i?"YES":"NO")<<endl
#define Yes(i) cout<<(i?"Yes":"No")<<endl
using namespace std;
//
const int INF=1e9+7;
const int mod=1e9+7;
//
int main(){
  int N;
  while(1){
    cin>>N;
    if(N==0){
      break;
    }
    VE V;
    FOR(i,0,N){
      string S;
      cin>>S;
      V.PB((int)S.size());
    }
    FOR(i,0,N){
      int sum=0;
      int now=i;
      while(sum<31){
        sum+=V[now];
        now++;
      }
      if(sum==31){
        cout<<i+1<<endl;
        break;
      }
    }
  }
  return 0;
}

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

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

int main() {
  int N;
  while (cin >> N, N) {
	vector<string> a(N); for (int i = 0; i < N; ++i) cin >> a[i];
	for (int i = 0; i < N; ++i) {
	  bool ok = true;
	  int j = i;
	  for (int it = 0; it < 5; ++it) {
		string str = "";
		while (j < N && str.size() < len[it]) str += a[j++];
		if (str.size() != len[it]) {
		  ok = false;
		  break;
		}
	  }
	  if (ok) {
		cout << i+1 << endl;
		break;
	  }
	}
  }
}

C++: #include <stdio.h>
#include <algorithm>
#include <iostream>
#include <vector>
#include <string>
using namespace std;
int make(int w,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){
                end=1;
              }
            }
          }
        }
      }
      if(end==1) break;
    }
    printf("%d\n",k+1);
    scanf ("%d",&n);
  }
}


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