Matrix reader

SUBROUTINE Lectura_Matrices
    USE DATOS
    IMPLICIT NONE
    INTEGER I,J
    OPEN(1,FILE="Matrices_Jacobi.txt")
    READ(1,*)
    DO I=1,N_Filas
        READ(1,*)(A(I,J),J=1,N_Columnas)
    END DO
    READ(1,*)
    DO I=1,N_Filas
        READ(1,*)B(I)
    END DO
    READ(1,*)
    DO I=1,N_Filas
        READ(1,*)X(i)
    END DO
END SUBROUTINE