#include <stdio.h>
#include <math.h>
char toNotationUnit(double value,float *out) {
        double val;
		char notacoes[] = {'y','z','a','f','p','n','u','m',' ','k','M','G','T','P','E','Z','Y'};
        int counter=8;
        char unit;
        val = value>0?value:-value;
        if(val < 1) {
                while( (val < 1.00) & (counter != 0)) {
                        counter--;
                        val=val*(double)1000;
                }
        }else{
                while((val >= 1000) & (counter != 16)) {
                        counter++;
                        val=val/(double)1000;
                }
        }
        unit = notacoes[counter];
        val = round(val*(double)100)/(double)100;
        *out = (float) value>0?val:-val;
        return unit;
}
 
int main() {
  double x = -1230000;
  float res;
  char t;
  t = toNotationUnit(x,&res);
  printf("%.2F%c",res,t);
  return 0;
}