include the mbed library with this snippet

#include "mbed.h"

Ticker tickerLed;
 
//Four user LEDs, LD3 (orange), LD4 (green), LD5 (red) and LD6 (blue)
DigitalOut led3(PD_13,0);
DigitalOut led4(PD_12,0);
DigitalOut led5(PD_14,0);
DigitalOut led6(PD_15);

// Кнопка поиска
//==============================================================================================================
DigitalIn button(PD_10);
//==============================================================================================================

// Последовательный порт
//==============================================================================================================
Serial debug(PB_6,PA_10);    // Serial1 tx rx
Serial configBT(PA_2,PA_3);  // Serial2 tx rx
//Serial slave(PC_10,PC_11);   // Serial3 tx rx
//Serial modem(PA_0,PA_1);     // Serial4 tx rx
//==============================================================================================================


void ToggleLed()
{
    int tmp;
    tmp  = led3;
    led3 = led4;              
    led4 = led6;  
    led6 = led5;
    led5 = tmp;
}


int main()
{
    bool bStart = false;
    
    led3 = 1;
    led5 = 0;  
    led6 = 0;                
    led4 = 0;
    
    wait(1.0f);
    
    // Init the ticker with the address of the function (toggle_led) to be attached and the interval (500 ms)
    tickerLed.attach(&ToggleLed, 1.0);
    
    while (true)
    {
        int nBtn = button.read();
        if (!nBtn && !bStart)
        {
            bStart = true;
            //debug.printf("v\n");
        }
        if (nBtn && bStart)
        {
            bStart = false;
            //debug.printf("!\n");
        }
    }
}