Go: package main

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

type Matrix struct {
	r int // num of row
	c int // num of column
}

type Range struct {
	start int // index, inclusive
	end   int // index, inclusive
}

func (r Range) length() int {
	return r.end - r.start + 1
}

func calcMultiplication(x, y Matrix) (Matrix, int) {
	if x.c != y.r {
		panic("cannnot calculate")
	}
	return Matrix{x.r, y.c}, x.r * y.c * x.c
}

func calcMinMatrixChainMultiplication(matrices []Matrix, r Range, memo map[Range]int) (Matrix, int) {
	if v, ok := memo[r]; ok {
		return Matrix{matrices[r.start].r, matrices[r.end].c}, v
	}
	if r.length() == 0 {
		panic("must not be empty")
	} else if r.length() == 1 {
		return matrices[r.start], 0
	}

	var minCount int = math.MaxInt32

	for i := 0; i < r.length()-1; i++ {
		formerRange := Range{r.start, r.start + i}
		latterRange := Range{r.start + i + 1, r.end}
		matF, countF := calcMinMatrixChainMultiplication(matrices, formerRange, memo)
		matL, countL := calcMinMatrixChainMultiplication(matrices, latterRange, memo)
		_, countFL := calcMultiplication(matF, matL)
		count := countF + countL + countFL
		if count < minCount {
			minCount = count
		}
	}
	memo[r] = minCount
	return Matrix{matrices[r.start].r, matrices[r.end].c}, minCount
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	n, _ := nextInt(sc)
	matrices := make([]Matrix, n)
	for i := 0; i < n; i++ {
		r, _ := nextInt(sc)
		c, _ := nextInt(sc)
		matrices[i] = Matrix{r, c}
	}
	memo := make(map[Range]int)
	_, resultCount := calcMinMatrixChainMultiplication(matrices, Range{0, len(matrices) - 1}, memo)
	fmt.Println(resultCount)
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: #include<iostream>
#include<algorithm>
using namespace std;
static const int N=100;
 
int main(){
    int n,p[N+1],m[N+1][N+1];
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>p[i-1]>>p[i];
    }
 
    for(int i=1;i<=n;i++)    m[i][i]=0;
    for(int l=2;l<=n;l++){
        for(int i=1;i<=n-l+1;i++){
            int j=i+l-1;
            m[i][j]=(1<<21);
            for(int k=i;k<=j;k++){
                m[i][j]=min(m[i][j],m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
            }
        }
    }
    cout<<m[1][n]<<endl;
 
    return 0;
}

C++: #include <stdio.h>
#include <limits.h>
#define MAX 100

int main(){
  int n, m[MAX+1][MAX+1];
  int i, j, k, r, min;
	
  scanf("%d", &n);
  for(i=1;i<=n;++i) {
    scanf("%d %d", &m[i][i-1], &m[i+1][i]);
    m[i][i] = 0;
  }
	
  for(r=2;r<=n;++r){
    for(i=1;i<=n-r+1;++i){
      j=i+r-1;
      m[i][j] = INT_MAX;
      for(k=i;k<=j-1;++k){
	min = m[i][k]+m[k+1][j]+m[i][i-1]*m[k+1][k]*m[j+1][j];
	if(m[i][j] > min) m[i][j] = min;
      }
    }
  }
  printf("%d\n", m[1][n]);
  return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define _USE_MATH_DEFINES
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int num = 105;
int p[num];
int main() {
	int n;
	cin >> n;
	for (int i = 1; i <= n; i++) {
		scanf("%d%d", &p[i-1], &p[i]);
	}
	int m[num][num];
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= n; j++) {
			m[i][j] = 999999999999;
		}
	}
	for (int i = 1; i <= n; i++) m[i][i] = 0;
	for (int l = 1; l < n; l++) {
		for (int i = 1; i < n - l + 1; i++) {
			int j = i + l;
			for (int k = i; k < j; k++)
				m[i][j] = min(m[i][j], m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]);
		}
	}
	cout << m[1][n] << endl;
	return 0;
}

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

constexpr int N=100;

int main(){
   int n, p[N+1], m[N+1][N+1];
   cin >> n;
   for(int i=1; i<=n; i++){
      cin >> p[i-1] >> p[i];
   }

   for(int i=1; i<=n; i++) m[i][i]=0;
   for(int l=2; l<=n; l++){
      for(int i=1; i<=n; i++){
         int j=i+l-1;
         m[i][j]=(1<<21);
         for(int k=i; k<=j-1; k++)
            m[i][j]=min(m[i][j], m[i][k]+m[k+1][j]+p[i-1]*p[k]*p[j]);
      }
   }

   cout << m[1][n] << endl;
}

C++: #include <iostream>
#include <algorithm>
#include <cstdint>

using namespace std;

static const int N = 100;
static int m[N + 1][N + 1] = {}, p[N + 1] = {};

static inline void matrixChainMultiplication(int n) {
  for (int l = 2; l <= n; l++) {
    for (int i = 1; i <= n - l + 1; i++) {
      int j = i + l - 1;
      m[i][j] = INT_MAX;
      for (int k = i; k <= j - 1; k++) {
        m[i][j] = min(m[i][j], m[i][k] + m[k + 1][j] + p[i - 1] * p[k] * p[j]); 
      }
    }
  }
}

int main() {
  int n;
  cin >> n;
  
  for (int i = 1; i <= n; i++) {
    cin >> p[i - 1] >> p[i];
  }

  matrixChainMultiplication(n);
  
  cout << m[1][n] << endl;

  return 0;
}

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

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

  int n; cin >> n;
  vector<int> p(n+1);
  cin >> p[0] >> p[1];
  for(int i = 0; i < n-2; i++){
    int a, b; cin >> a >> b;
    p[i+2] = b;
  }
  {
    int a, b; cin >> a >> b;
    p[n] = b;
  }

  int dp[101][101];
  memset(dp, 0, sizeof(dp));

  n = p.size() - 1;
  for(int l = 2; l <= n; l++){
    for(int i = 1; i <= n-l+1; i++){
      int j = i+l-1;
      dp[i][j] = INT_MAX/10;
      for(int k = i; k < j; k++){
        dp[i][j] = min(dp[i][j], dp[i][k] + dp[k+1][j] + p[i-1]*p[k]*p[j]);
      }
    }
  }
  cout << dp[1][n] << endl;
  return 0;
}

C++: #include "bits/stdc++.h"

#define REP(i,num) for(ll i=0;i<(num);++i)
#define LOOP(i) while(i--)
#define ALL(c) c.begin(),c.end()
#define PRINTALL(c) for(auto pitr=c.begin();pitr!=c.end();++pitr){cout<<*pitr;if(next(pitr,1)!=c.end())cout<<' ';}cout<<endl;
#define PAIRCOMP(c,comp) [](const pair<ll,ll>& lhs,const pair<ll,ll>& rhs){return lhs.c comp rhs.c;}

using namespace std;
using ll = long long;
using vll = vector<ll>;
using vvll = vector<vector<ll>>;

constexpr ll atcoder_mod = 1e9+7;

template<typename T=ll>
T in(){T x; cin >> x; return (x);}
template<typename T=ll,typename C=vector<T>>
C vecin(int N){C x(N);REP(i,N){x[i]=in<T>();}return move(x);}

void vout(){cout << endl;}
template<typename Head,typename... Tail>
void vout(Head&& h,Tail&&... t){cout << ' ' << h;vout(forward<Tail>(t)...);}
void out(){cout << endl;}
template<typename Head,typename... Tail>
void out(Head&& h,Tail&&... t){cout << h;vout(forward<Tail>(t)...);}

template<typename T>
bool chmax(T& a,T b){if(a<b){a=b;return true;}return false;}
template<typename T>
bool chmin(T& a,T b){if(a>b){a=b;return true;}return false;}

vector<pair<ll,ll>> P;
vvll memo;

ll dfs(int l,int r){
	if(memo[l][r]>=0) return memo[l][r];
	if(r-l<2){
		return 0;
	}
	
	ll V=1LL<<60;
	for(int i=l+1;i<r;i++){
		V = min(V,dfs(l,i)+dfs(i,r)+P[l].first*P[i].first*P[r-1].second);
	}
	memo[l][r] = V;
	return V;
}

int main(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(10);

	int N=in();
	P.resize(N);
	memo.resize(N+1,vll(N+1,-1));
	REP(i,N){
		P[i].first=in();
		P[i].second=in();
	}
	
	out(dfs(0,N));
	return 0;
}