bale.cpp

#include <cstdio>
#include <cstring>
#define MAXN 100010
#define MAXS 1000010
#define max(A,B) (A)>(B)?(A):(B)

int  MAX = 1000001;
int bit[MAXS];

void insere(int x){
	while(x < 1000005){
		bit[x]++;
		x += (x & -x);
	}
}

int soma_ate(int x){
	int s = 0;
	while(x > 0){
		s += bit[x];
		x -= (x & -x);
	}
	return s;
}

int main(){
	
	int n;
	memset(bit,0,sizeof bit);
	scanf("%d",&n);
	
	int resp=0;
	int hab[MAXN];
	int maior=0;
	for(int i = 1;i<=n;i++){
		scanf("%d",&hab[i]);
		maior = max(maior,hab[i]);
	}
		
	for(int i = 1;i<=n;i++){
		insere(hab[i]);
		resp += soma_ate(maior) - soma_ate(hab[i]);
	}
	printf("%d\n",resp);
	
	return 0;
}