#include<iostream>

#include<cstring>

#include<cstdio>

#include<queue>

using namespace std;

inline int rd(){

    int ret=,f=;char c;

    while(c=getchar(),!isdigit(c))f=c=='-'?-:;

    while(isdigit(c))ret=ret*+c-'',c=getchar();

    return ret*f;

}

const int MAXN=;

int a[MAXN],d[MAXN];

queue<int> Q1,Q2;

int n,ans;

int main(){

    freopen("range.in","r",stdin);

    freopen("range.out","w",stdout);

    n=rd();

    for(int i=;i<=n;i++) a[i]=rd();

    for(int i=;i<=n;i++){

        d[i]=a[i]-a[i-];

        if(d[i]>) ans+=d[i];

    }

    d[n+]=-(<<);

    printf("%d\n",ans);

    int j=;

    for(int i=;i<=n;i++){

        if(d[i]==) continue;

        while(d[i]!=){

            if(d[j]>=){j++;continue;}

            d[i]-=;

            d[j]+=;

            printf("%d %d\n",i,j-);

        }

    }

    return ;

}